Tesla Model S and X owners with Autopilot enabled have another fun Easter Egg option at their disposal: Rainbow Road Mode. Yes, as in Mario Kart.
As discovered by Tesla owners on Reddit, it replaces the standard driving graphics in Autopilot mode with a hyper-colorful striped roadway that accelerates to match the varying speed of the vehicle, and includes lane change animations.
Reddit user majerus1223 noted that it's activated by engaging Autopilot and then quickly pulling on the control stalk four times (thankfully, you don't have to enter the famous Konami Code while driving). While some initially questioned if this was an intentional joke on Tesla's part (like the submarine mode that Tesla hid in the Model S software for a year before somebody found it), or a debugging mode for the autopilot that was unintentionally left accessible in the latest firmware update, Tesla CEO Elon Musk clarified that it's an intentional Easter Egg:
Activate autopilot 4X in quick succession for psychedelic cowbell road. And, yes, we are adding more cowbell soon.— Elon Musk (@elonmusk) April 11, 2016
As if you needed another reason to enable Autopilot on your Model S or Model X, here you have it: Mario Kart Mode! No word on if you get any Koopa shells or banana peels while in Rainbow Road mode...